//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2011 Greenplum, Inc.
//
//	@filename:
//		CParseHandlerDistinctComp.cpp
//
//	@doc:
//		Implementation of the SAX parse handler class for parsing distinct
//		comparison operators.
//---------------------------------------------------------------------------


#include "naucrates/dxl/parser/CParseHandlerScalarOp.h"
#include "naucrates/dxl/parser/CParseHandlerFactory.h"

#include "naucrates/dxl/operators/CDXLOperatorFactory.h"

#include "naucrates/dxl/parser/CParseHandlerDistinctComp.h"

using namespace gpdxl;


XERCES_CPP_NAMESPACE_USE

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerDistinctComp::CParseHandlerDistinctComp
//
//	@doc:
//		Constructor
//
//---------------------------------------------------------------------------
CParseHandlerDistinctComp::CParseHandlerDistinctComp
	(
	CMemoryPool *mp,
	CParseHandlerManager *parse_handler_mgr,
	CParseHandlerBase *parse_handler_root
	)
	:
	CParseHandlerScalarOp(mp, parse_handler_mgr, parse_handler_root),
	m_dxl_op(NULL)
{
}

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerDistinctComp::StartElement
//
//	@doc:
//		Processes a Xerces start element event
//
//---------------------------------------------------------------------------
void
CParseHandlerDistinctComp::StartElement
	(
	const XMLCh* const, // element_uri,
	const XMLCh* const element_local_name,
	const XMLCh* const, // element_qname
	const Attributes& attrs
	)
{
	if(0 != XMLString::compareString(CDXLTokens::XmlstrToken(EdxltokenScalarDistinctComp), element_local_name))
	{
		CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
		GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag, str->GetBuffer());
	}
	
	// parse and create distinct operator
	m_dxl_op = (CDXLScalarDistinctComp *) CDXLOperatorFactory::MakeDXLDistinctCmp(m_parse_handler_mgr->GetDXLMemoryManager(), attrs);
	
	// create and activate the parse handler for the children nodes in reverse
	// order of their expected appearance
	
	// parse handler for right scalar node
	CParseHandlerBase *right_child_parse_handler = CParseHandlerFactory::GetParseHandler(m_mp, CDXLTokens::XmlstrToken(EdxltokenScalar), m_parse_handler_mgr, this);
	m_parse_handler_mgr->ActivateParseHandler(right_child_parse_handler);
	
	// parse handler for left scalar node
	CParseHandlerBase *left_child_parse_handler = CParseHandlerFactory::GetParseHandler(m_mp, CDXLTokens::XmlstrToken(EdxltokenScalar), m_parse_handler_mgr, this);
	m_parse_handler_mgr->ActivateParseHandler(left_child_parse_handler);
	
	// store parse handlers
	this->Append(left_child_parse_handler);
	this->Append(right_child_parse_handler);

}

//---------------------------------------------------------------------------
//	@function:
//		CParseHandlerDistinctComp::EndElement
//
//	@doc:
//		Processes a Xerces end element event
//
//---------------------------------------------------------------------------
void
CParseHandlerDistinctComp::EndElement
	(
	const XMLCh* const, // element_uri,
	const XMLCh* const element_local_name,
	const XMLCh* const // element_qname
	)
{
	if(0 != XMLString::compareString(CDXLTokens::XmlstrToken(EdxltokenScalarDistinctComp), element_local_name))
	{
		CWStringDynamic *str = CDXLUtils::CreateDynamicStringFromXMLChArray(m_parse_handler_mgr->GetDXLMemoryManager(), element_local_name);
		GPOS_RAISE(gpdxl::ExmaDXL, gpdxl::ExmiDXLUnexpectedTag, str->GetBuffer());
	}

	// construct node from the created child nodes
	m_dxl_node = GPOS_NEW(m_mp) CDXLNode(m_mp, m_dxl_op);

	CParseHandlerScalarOp *left_child_parse_handler = dynamic_cast<CParseHandlerScalarOp *>((*this)[0]);
	CParseHandlerScalarOp *right_child_parse_handler = dynamic_cast<CParseHandlerScalarOp *>((*this)[1]);

	// add constructed children
	AddChildFromParseHandler(left_child_parse_handler);
	AddChildFromParseHandler(right_child_parse_handler);
	
	// deactivate handler
	m_parse_handler_mgr->DeactivateHandler();
}

// EOF

